Preheat your oven to 180 degrees and line a 20cm square baking tin with greaseproof paper.
In a large pan, gently melt the butter, syrup and sugar together until all the granules have dissolved, taking care to not let the mixture get too hot.
Stir in the oats, ground almonds and essence then set aside to cool for a couple of minutes (this ensures that not only is it cold enough to touch, the caramel will soak all the way through the oats).
Tip just over half the mixture into the prepared tin and, using your fingers or the back of a spoon, press it down so it reaches the corners and makes a flat surface.
Scatter the blackberries over then push them down gently into the mixture.
Tip over the remaining oats (you’ll need to wash your hands after squishing the berries!) and press down once again to cover the fruit.
Bake in the centre of the oven for 18-20 minutes for a softer flapjack, or up to 25 if you like it towards the crispy end of the scale!